Irregular Periods After Antibiotics: A Medical Inquiry

Question
I am 28 years old, the first day of my last period was May 10th, 2005.  I have been on the pill for years and started them back after I had my child in Sept. of 2002.  I have always had a regular period and started at the same time every month.  In early may my docter put me on 30 days of Cephlexin and 10 days of Dycocyclin because I had some moles removed and he didn't want me to get a staff infection.  I completed my antibiotics at the end of may, first of july, don't remember which.  I have not had a period since.  I was scared I may have become pregnant and when I didn't start my period in June I quit taking my b/c pills.  I stayed off of them for over a month.  When I found out through my obgyn that I was not in fact pregnant, I began taking them again about 2 weeks ago.  I still have not had a period this month and I should have already had it.  So for 2 months my period has been off and I am so tired that I can't see straight, I just want to sleep all the time, no docter can find anything wrong with me and I took another pregnancy test this morning and it was negative.  My husband and I did have unprotected sex on the 18th of this month (july), Is there anyway possible that I could have gotten pregnant and it is just not showing up yet and if not, why am I feeling this way and why am I not having a period, I feel like my whole body is out of control and no one can help me.  

Answer
You should not have stopped taking the pills, even if you thought you may have become pregnant. Birth control pills can be taken even if you are pregnant, as long as you stop them before the start of the second trimester of pregnancy. If you stopped the pills in June and did not get your period, you probably did not ovulate. If you have not gotten your period since then, you should ask your gynecologist to induce your period for you using Provera 10mg twice a day for 5 days and you should get your period within 10 days. Then, once you start your period, you should start the birth control pills once again. If you have any doubts as to being pregnant, you can take two blood tests for pregnancy (Beta HCG) 48 hours apart. If there is a doubling of the results in 48 hours, it indicates a viable pregnancy. If there is a halving of the results in 48 hours, it indicates a miscarriage. If the value of both tests is less thn 5, it means that you were never pregnant. Don't worry.